In addition to conventional computing systems for the office, home and mobile environment, there are now many small information processing devices that have significant processing power. These small information processing devices include personal digital assistants with touch screens, handheld personal computing devices, cellular phones and watches. These small information processing devices have no keys or a very limited key set. They rely on other forms of manual input such as stylus/touch screen or, if there is a limited key set such as on a cellular phone, each key must be pressed multiple times to select a particular character as input.
The difficulty with the stylus/touch screen input technique is that it requires a sophisticated character recognition program to interpret the user's hand writing. Also there are restrictive rules on the handwritten character strokes by the user. Alternatively, the touch screen may display a keyboard, sometimes called a soft keyboard, and the user touches the key on the screen with the stylus; i.e. hunt and peck entry. For small display screen, this touching a character location must be precise. Either process for using stylus and touch screen to enter input information is slow.
The difficulty with data entry using multiple pushes on a key in a limited key set is that the process does not lend itself to muscle memory for the user. For example, in the telephone key set, pressing a number key one, two or three times will enter three different alphabetic characters. Further, this mode of alphabetic character entry occurs only after entering a function that expects alphabetic characters. The user must remember which key to press and how many times to press it. In addition to the process not being intuitive and not leading to muscle memory, the entry process using multiple presses of a selected key from a key set is also very slow.